Diamond Lattice Model

Lattice models are attractive, useful teaching tools and not easy to construct. The diamond lattice is a traditional example. Diamond crystallizes to form a cubic cell in which each carbon atom forms four bonds. The diamond lattice has octahedral symmetry and the view into each of the 12 edges of the cell is the same.

The Naval Research Laboratory in Washington has long had a Division for the Structure of Matter. NRL hosts a large collection of crystal lattice structures.
Note : The NRL no longer hosts these pages - new links below -
https://homepage.univie.ac.at/michael.leitner/lattice/spcgrp/index.html
On one of their web pages I found a downloadable set of coordinates for the diamond unit cell.
https://homepage.univie.ac.at/michael.leitner/lattice/struk/a4.html
As in "Buckyballs" I used a fortran program to make openSCAD module calls. Expand_diamond.f takes the unit cell coordinates of diamond, expands them to a 27 cell cube, and outputs the required calls.

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